William Michael Phillips (born 29 August 1982) is a Welsh rugby union player who plays at scrum-half.

Tall and powerful, unusual properties in a scrum half, he has been compared to ex-Wales international Terry Holmes.

[2][3][4] Citing his lack of first team appearances as the main reason,[3][5] in 2005 Phillips signed for the Cardiff Blues starting most matches,[4] partnering fellow former Welsh Under-21 player Nicky Robinson.

Following Marshall's departure to Montpellier, Phillips had the chance to make the position his own but for a knee ligament injury, allowing the emergence of new signing Jamie Nutbrown to take the role.

In October 2013, he was sacked from Bayonne for repeated misconduct, with the final incident being drunk at an analysis session following the loss to London Wasps in the Amlin Cup.

[7][8] On 2 December 2013, Phillips joined French club Racing Métro, linking up with fellow Wales internationals Jamie Roberts and Dan Lydiate.

[10] On 26 November 2017 Philips briefly came out of retirement to join the Scarlets squad as cover due to injuries at scrum half and came on as a second-half substitute in their 34–30 Pro 14 win against the Southern Kings.

[11] Phillips represented Wales at Under-21 level where he played with fellow Cardiff player Nicky Robinson.

Phillips also started against France, as Wales claimed their second grand slam in four years with a 29–12 hammering of Les Bleus.

A week after the grand slam a knee ligament injury ruled him out for six months, meaning he would miss the tour of South Africa and the Autumn Internationals.

On 21 April 2009, Phillips was named as one of 13 Welsh players for the 2009 British & Irish Lions tour to South Africa.

[21] On 8 September 2015, Philips was called into the World Cup squad to cover the injured Rhys Webb who has been ruled out.